package field_method13;

public class Circle {
    double r;
    public void area(){
double pai=3.14;
double s =pai*r*r;

System.out.println("面积为"+s);
    }
    public void area2(double pai){
        double s=pai*r*r;
        System.out.println("面积为"+s);
    }
    public double area2(double r,double pai){
        double s=pai *r*r;
        return s;
    }
}













